Luminaires with automated and remotely controllable functionality are well known in the entertainment and architectural lighting markets. Such products are commonly used in theatres, television studios, concerts, theme parks, night clubs and other venues. A typical product will commonly provide control over the pan and tilt functions of the luminaire allowing the operator to control the direction the luminaire is pointing and thus the position of the light beam on the stage or in the studio. Typically this position control is done via control of the luminaire's position in two orthogonal rotational axes usually referred to as pan and tilt. Many products provide control over other parameters such as the intensity, color, focus, beam size, beam shape and beam pattern. The beam pattern is often provided by a stencil or slide called a gobo which may be a steel, aluminum, or etched glass pattern. The products manufactured by Robe Show Lighting such as the ColorSpot 700E are typical of the art.
The optical systems of such luminaires may include a beam shaping optical element through which the light is constrained to pass. A beam shaping element may comprise an asymmetric or lenticular lens or collection of lenses that constrain a light beam that is symmetrical and circular in cross section to one that is asymmetrical and predominantly elliptical or rectangular in cross section. A prior art automated luminaire may contain a plurality of such beam shapers each of which may have a greater or lesser effect on the light beam and that may be overlapped to produce a composite effect. For example a weak beam shaper may constrain a circular beam that has a symmetrical beam angle of 20° in all directions into a primarily elliptical beam that has a major axis of 30° and a minor axis of 15°. A more powerful beam shaper may constrain a circular beam that has a symmetrical beam angle of 20° in all directions into a primarily elliptical beam that has a major axis of 40° and a minor axis of 10°. It is also common in prior art luminaires to provide the ability to rotate the beam shaper along the optical axis such that the resultant symmetrical elliptical beam may also be rotated. U.S. Pat. Nos. 5,665,305; 5,758,955; 5,980,066 and 6,048,080 disclose such a system where a plurality of discrete lens elements is used to control the shape of a light beam.
FIG. 1 illustrates a typical multiparameter automated luminaire system 10. These systems commonly include a plurality of multiparameter automated luminaires 12 which typically each contain on-board a light source (not shown), light modulation devices, electric motors coupled to mechanical drive systems and control electronics (not shown). In addition to being connected to mains power either directly or through a power distribution system (not shown), each automated luminaire 12 is connected in series or in parallel to data link 14 to one or more control desks 15. The automated luminaire system 10 is typically controlled by an operator through the control desk 15.
Prior art beam shapers often require installation internally within the luminaire and are not suitable for optical systems where an array of a number of discrete emitters, such as Light Emitting Diodes (LEDs), is used to produce the beam. Instead they rely on the optical path having a focus point that is small compared to the overall diameter of the beam in which the beam shaping can be situated.
There is a need for an improved beam shaper mechanism for automated luminaires that is simple to install or remove from a luminaire, which provides the ability to smoothly and continuously adjust the angle of eccentricity of the constrained light beam for a light beam produced by an array of discrete emitters such as LEDs.